drbd: receiving of big packets, for payloads between 64kByte and 4GByte

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

1 files changed, 168 insertions, 221 deletions

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 9b3321e2c3cd..fe308644a63c 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -720,14 +720,14 @@ out:
 static int drbd_send_fp(struct drbd_conf *mdev,
         struct socket *sock, enum drbd_packets cmd)
 {
-        struct p_header80 *h = (struct p_header80 *) &mdev->data.sbuf.header;
+        struct p_header80 *h = &mdev->data.sbuf.header.h80;
 
         return _drbd_send_cmd(mdev, sock, cmd, h, sizeof(*h), 0);
 }
 
 static enum drbd_packets drbd_recv_fp(struct drbd_conf *mdev, struct socket *sock)
 {
-        struct p_header80 *h = (struct p_header80 *) &mdev->data.sbuf.header;
+        struct p_header80 *h = &mdev->data.rbuf.header.h80;
         int rr;
 
         rr = drbd_recv_short(mdev, sock, h, sizeof(*h), 0);
@@ -944,22 +944,27 @@ out_release_sockets:
         return -1;
 }
 
-static int drbd_recv_header(struct drbd_conf *mdev, struct p_header80 *h)
+static int drbd_recv_header(struct drbd_conf *mdev, enum drbd_packets *cmd, unsigned int *packet_size)
 {
+        union p_header *h = &mdev->data.rbuf.header;
         int r;
 
         r = drbd_recv(mdev, h, sizeof(*h));
-
         if (unlikely(r != sizeof(*h))) {
                 dev_err(DEV, "short read expecting header on sock: r=%d\n", r);
                 return FALSE;
-        };
-        h->command = be16_to_cpu(h->command);
-        h->length  = be16_to_cpu(h->length);
-        if (unlikely(h->magic != BE_DRBD_MAGIC)) {
+        }
+
+        if (likely(h->h80.magic == BE_DRBD_MAGIC)) {
+                *cmd = be16_to_cpu(h->h80.command);
+                *packet_size = be16_to_cpu(h->h80.length);
+        } else if (h->h95.magic == BE_DRBD_MAGIC_BIG) {
+                *cmd = be16_to_cpu(h->h95.command);
+                *packet_size = be32_to_cpu(h->h95.length);
+        } else {
                 dev_err(DEV, "magic?? on data m: 0x%lx c: %d l: %d\n",
-                    (long)be32_to_cpu(h->magic),
-                    h->command, h->length);
+                    (long)be32_to_cpu(h->h80.magic),
+                    h->h80.command, h->h80.length);
                 return FALSE;
         }
         mdev->last_received = jiffies;
@@ -1266,17 +1271,12 @@ int w_e_reissue(struct drbd_conf *mdev, struct drbd_work *w, int cancel) __relea
         return 1;
 }
 
-static int receive_Barrier(struct drbd_conf *mdev, struct p_header80 *h)
+static int receive_Barrier(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned int data_size)
 {
         int rv, issue_flush;
-        struct p_barrier *p = (struct p_barrier *)h;
+        struct p_barrier *p = &mdev->data.rbuf.barrier;
         struct drbd_epoch *epoch;
 
-        ERR_IF(h->length != (sizeof(*p)-sizeof(*h))) return FALSE;
-
-        rv = drbd_recv(mdev, h->payload, h->length);
-        ERR_IF(rv != h->length) return FALSE;
-
         inc_unacked(mdev);
 
         if (mdev->net_conf->wire_protocol != DRBD_PROT_C)
@@ -1570,21 +1570,12 @@ fail:
         return FALSE;
 }
 
-static int receive_DataReply(struct drbd_conf *mdev, struct p_header80 *h)
+static int receive_DataReply(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned int data_size)
 {
         struct drbd_request *req;
         sector_t sector;
-        unsigned int header_size, data_size;
         int ok;
-        struct p_data *p = (struct p_data *)h;
-
-        header_size = sizeof(*p) - sizeof(*h);
-        data_size   = h->length  - header_size;
-
-        ERR_IF(data_size == 0) return FALSE;
-
-        if (drbd_recv(mdev, h->payload, header_size) != header_size)
-                return FALSE;
+        struct p_data *p = &mdev->data.rbuf.data;
 
         sector = be64_to_cpu(p->sector);
 
@@ -1610,20 +1601,11 @@ static int receive_DataReply(struct drbd_conf *mdev, struct p_header80 *h)
         return ok;
 }
 
-static int receive_RSDataReply(struct drbd_conf *mdev, struct p_header80 *h)
+static int receive_RSDataReply(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned int data_size)
 {
         sector_t sector;
-        unsigned int header_size, data_size;
         int ok;
-        struct p_data *p = (struct p_data *)h;
-
-        header_size = sizeof(*p) - sizeof(*h);
-        data_size   = h->length  - header_size;
-
-        ERR_IF(data_size == 0) return FALSE;
-
-        if (drbd_recv(mdev, h->payload, header_size) != header_size)
-                return FALSE;
+        struct p_data *p = &mdev->data.rbuf.data;
 
         sector = be64_to_cpu(p->sector);
         D_ASSERT(p->block_id == ID_SYNCER);
@@ -1767,23 +1749,14 @@ static int drbd_wait_peer_seq(struct drbd_conf *mdev, const u32 packet_seq)
 }
 
 /* mirrored write */
-static int receive_Data(struct drbd_conf *mdev, struct p_header80 *h)
+static int receive_Data(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned int data_size)
 {
         sector_t sector;
         struct drbd_epoch_entry *e;
-        struct p_data *p = (struct p_data *)h;
-        int header_size, data_size;
+        struct p_data *p = &mdev->data.rbuf.data;
         int rw = WRITE;
         u32 dp_flags;
 
-        header_size = sizeof(*p) - sizeof(*h);
-        data_size   = h->length  - header_size;
-
-        ERR_IF(data_size == 0) return FALSE;
-
-        if (drbd_recv(mdev, h->payload, header_size) != header_size)
-                return FALSE;
-
         if (!get_ldev(mdev)) {
                 if (__ratelimit(&drbd_ratelimit_state))
                         dev_err(DEV, "Can not write mirrored data block "
@@ -2066,20 +2039,15 @@ int drbd_rs_should_slow_down(struct drbd_conf *mdev)
 }
 
 
-static int receive_DataRequest(struct drbd_conf *mdev, struct p_header80 *h)
+static int receive_DataRequest(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned int digest_size)
 {
         sector_t sector;
         const sector_t capacity = drbd_get_capacity(mdev->this_bdev);
         struct drbd_epoch_entry *e;
         struct digest_info *di = NULL;
-        struct p_block_req *p = (struct p_block_req *)h;
-        const int brps = sizeof(*p)-sizeof(*h);
-        int size, digest_size;
+        int size;
         unsigned int fault_type;
-
-
-        if (drbd_recv(mdev, h->payload, brps) != brps)
-                return FALSE;
+        struct p_block_req *p = &mdev->data.rbuf.block_req;
 
         sector = be64_to_cpu(p->sector);
         size   = be32_to_cpu(p->blksize);
@@ -2099,9 +2067,9 @@ static int receive_DataRequest(struct drbd_conf *mdev, struct p_header80 *h)
                 if (__ratelimit(&drbd_ratelimit_state))
                         dev_err(DEV, "Can not satisfy peer's read request, "
                             "no local data.\n");
-                drbd_send_ack_rp(mdev, h->command == P_DATA_REQUEST ? P_NEG_DREPLY :
+                drbd_send_ack_rp(mdev, cmd == P_DATA_REQUEST ? P_NEG_DREPLY :
                                  P_NEG_RS_DREPLY , p);
-                return drbd_drain_block(mdev, h->length - brps);
+                return TRUE;
         }
 
         /* GFP_NOIO, because we must not cause arbitrary write-out: in a DRBD
@@ -2113,7 +2081,7 @@ static int receive_DataRequest(struct drbd_conf *mdev, struct p_header80 *h)
                 return FALSE;
         }
 
-        switch (h->command) {
+        switch (cmd) {
         case P_DATA_REQUEST:
                 e->w.cb = w_e_end_data_req;
                 fault_type = DRBD_FAULT_DT_RD;
@@ -2128,7 +2096,6 @@ static int receive_DataRequest(struct drbd_conf *mdev, struct p_header80 *h)
         case P_OV_REPLY:
         case P_CSUM_RS_REQUEST:
                 fault_type = DRBD_FAULT_RS_RD;
-                digest_size = h->length - brps ;
                 di = kmalloc(sizeof(*di) + digest_size, GFP_NOIO);
                 if (!di)
                         goto out_free_e;
@@ -2142,10 +2109,10 @@ static int receive_DataRequest(struct drbd_conf *mdev, struct p_header80 *h)
                 if (drbd_recv(mdev, di->digest, digest_size) != digest_size)
                         goto out_free_e;
 
-                if (h->command == P_CSUM_RS_REQUEST) {
+                if (cmd == P_CSUM_RS_REQUEST) {
                         D_ASSERT(mdev->agreed_pro_version >= 89);
                         e->w.cb = w_e_end_csum_rs_req;
-                } else if (h->command == P_OV_REPLY) {
+                } else if (cmd == P_OV_REPLY) {
                         e->w.cb = w_e_end_ov_reply;
                         dec_rs_pending(mdev);
                         /* drbd_rs_begin_io done when we sent this request,
@@ -2173,7 +2140,7 @@ static int receive_DataRequest(struct drbd_conf *mdev, struct p_header80 *h)
 
         default:
                 dev_err(DEV, "unexpected command (%s) in receive_DataRequest\n",
-                    cmdname(h->command));
+                    cmdname(cmd));
                 fault_type = DRBD_FAULT_MAX;
                 goto out_free_e;
         }
@@ -2756,20 +2723,13 @@ static int cmp_after_sb(enum drbd_after_sb_p peer, enum drbd_after_sb_p self)
         return 1;
 }
 
-static int receive_protocol(struct drbd_conf *mdev, struct p_header80 *h)
+static int receive_protocol(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned int data_size)
 {
-        struct p_protocol *p = (struct p_protocol *)h;
-        int header_size, data_size;
+        struct p_protocol *p = &mdev->data.rbuf.protocol;
         int p_proto, p_after_sb_0p, p_after_sb_1p, p_after_sb_2p;
         int p_want_lose, p_two_primaries, cf;
         char p_integrity_alg[SHARED_SECRET_MAX] = "";
 
-        header_size = sizeof(*p) - sizeof(*h);
-        data_size   = h->length  - header_size;
-
-        if (drbd_recv(mdev, h->payload, header_size) != header_size)
-                return FALSE;
-
         p_proto         = be32_to_cpu(p->protocol);
         p_after_sb_0p   = be32_to_cpu(p->after_sb_0p);
         p_after_sb_1p   = be32_to_cpu(p->after_sb_1p);
@@ -2862,10 +2822,10 @@ struct crypto_hash *drbd_crypto_alloc_digest_safe(const struct drbd_conf *mdev,
         return tfm;
 }
 
-static int receive_SyncParam(struct drbd_conf *mdev, struct p_header80 *h)
+static int receive_SyncParam(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned int packet_size)
 {
         int ok = TRUE;
-        struct p_rs_param_95 *p = (struct p_rs_param_95 *)h;
+        struct p_rs_param_95 *p = &mdev->data.rbuf.rs_param_95;
         unsigned int header_size, data_size, exp_max_sz;
         struct crypto_hash *verify_tfm = NULL;
         struct crypto_hash *csums_tfm = NULL;
@@ -2879,29 +2839,29 @@ static int receive_SyncParam(struct drbd_conf *mdev, struct p_header80 *h)
                     : apv <= 94 ? sizeof(struct p_rs_param_89)
                     : /* apv >= 95 */ sizeof(struct p_rs_param_95);
 
-        if (h->length > exp_max_sz) {
+        if (packet_size > exp_max_sz) {
                 dev_err(DEV, "SyncParam packet too long: received %u, expected <= %u bytes\n",
-                    h->length, exp_max_sz);
+                    packet_size, exp_max_sz);
                 return FALSE;
         }
 
         if (apv <= 88) {
-                header_size = sizeof(struct p_rs_param) - sizeof(*h);
-                data_size   = h->length  - header_size;
+                header_size = sizeof(struct p_rs_param) - sizeof(struct p_header80);
+                data_size   = packet_size  - header_size;
         } else if (apv <= 94) {
-                header_size = sizeof(struct p_rs_param_89) - sizeof(*h);
-                data_size   = h->length  - header_size;
+                header_size = sizeof(struct p_rs_param_89) - sizeof(struct p_header80);
+                data_size   = packet_size  - header_size;
                 D_ASSERT(data_size == 0);
         } else {
-                header_size = sizeof(struct p_rs_param_95) - sizeof(*h);
-                data_size   = h->length  - header_size;
+                header_size = sizeof(struct p_rs_param_95) - sizeof(struct p_header80);
+                data_size   = packet_size  - header_size;
                 D_ASSERT(data_size == 0);
         }
 
         /* initialize verify_alg and csums_alg */
         memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);
 
-        if (drbd_recv(mdev, h->payload, header_size) != header_size)
+        if (drbd_recv(mdev, &p->head.payload, header_size) != header_size)
                 return FALSE;
 
         mdev->sync_conf.rate      = be32_to_cpu(p->rate);
@@ -3032,19 +2992,15 @@ static void warn_if_differ_considerably(struct drbd_conf *mdev,
                      (unsigned long long)a, (unsigned long long)b);
 }
 
-static int receive_sizes(struct drbd_conf *mdev, struct p_header80 *h)
+static int receive_sizes(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned int data_size)
 {
-        struct p_sizes *p = (struct p_sizes *)h;
+        struct p_sizes *p = &mdev->data.rbuf.sizes;
         enum determine_dev_size dd = unchanged;
         unsigned int max_seg_s;
         sector_t p_size, p_usize, my_usize;
         int ldsc = 0; /* local disk size changed */
         enum dds_flags ddsf;
 
-        ERR_IF(h->length != (sizeof(*p)-sizeof(*h))) return FALSE;
-        if (drbd_recv(mdev, h->payload, h->length) != h->length)
-                return FALSE;
-
         p_size = be64_to_cpu(p->d_size);
         p_usize = be64_to_cpu(p->u_size);
 
@@ -3148,16 +3104,12 @@ static int receive_sizes(struct drbd_conf *mdev, struct p_header80 *h)
         return TRUE;
 }
 
-static int receive_uuids(struct drbd_conf *mdev, struct p_header80 *h)
+static int receive_uuids(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned int data_size)
 {
-        struct p_uuids *p = (struct p_uuids *)h;
+        struct p_uuids *p = &mdev->data.rbuf.uuids;
         u64 *p_uuid;
         int i;
 
-        ERR_IF(h->length != (sizeof(*p)-sizeof(*h))) return FALSE;
-        if (drbd_recv(mdev, h->payload, h->length) != h->length)
-                return FALSE;
-
         p_uuid = kmalloc(sizeof(u64)*UI_EXTENDED_SIZE, GFP_NOIO);
 
         for (i = UI_CURRENT; i < UI_EXTENDED_SIZE; i++)
@@ -3241,16 +3193,12 @@ static union drbd_state convert_state(union drbd_state ps)
         return ms;
 }
 
-static int receive_req_state(struct drbd_conf *mdev, struct p_header80 *h)
+static int receive_req_state(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned int data_size)
 {
-        struct p_req_state *p = (struct p_req_state *)h;
+        struct p_req_state *p = &mdev->data.rbuf.req_state;
         union drbd_state mask, val;
         int rv;
 
-        ERR_IF(h->length != (sizeof(*p)-sizeof(*h))) return FALSE;
-        if (drbd_recv(mdev, h->payload, h->length) != h->length)
-                return FALSE;
-
         mask.i = be32_to_cpu(p->mask);
         val.i = be32_to_cpu(p->val);
 
@@ -3271,21 +3219,15 @@ static int receive_req_state(struct drbd_conf *mdev, struct p_header80 *h)
         return TRUE;
 }
 
-static int receive_state(struct drbd_conf *mdev, struct p_header80 *h)
+static int receive_state(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned int data_size)
 {
-        struct p_state *p = (struct p_state *)h;
+        struct p_state *p = &mdev->data.rbuf.state;
         enum drbd_conns nconn, oconn;
         union drbd_state ns, peer_state;
         enum drbd_disk_state real_peer_disk;
         enum chg_state_flags cs_flags;
         int rv;
 
-        ERR_IF(h->length != (sizeof(*p)-sizeof(*h)))
-                return FALSE;
-
-        if (drbd_recv(mdev, h->payload, h->length) != h->length)
-                return FALSE;
-
         peer_state.i = be32_to_cpu(p->state);
 
         real_peer_disk = peer_state.disk;
@@ -3395,9 +3337,9 @@ static int receive_state(struct drbd_conf *mdev, struct p_header80 *h)
         return TRUE;
 }
 
-static int receive_sync_uuid(struct drbd_conf *mdev, struct p_header80 *h)
+static int receive_sync_uuid(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned int data_size)
 {
-        struct p_rs_uuid *p = (struct p_rs_uuid *)h;
+        struct p_rs_uuid *p = &mdev->data.rbuf.rs_uuid;
 
         wait_event(mdev->misc_wait,
                    mdev->state.conn == C_WF_SYNC_UUID ||
@@ -3406,10 +3348,6 @@ static int receive_sync_uuid(struct drbd_conf *mdev, struct p_header80 *h)
 
         /* D_ASSERT( mdev->state.conn == C_WF_SYNC_UUID ); */
 
-        ERR_IF(h->length != (sizeof(*p)-sizeof(*h))) return FALSE;
-        if (drbd_recv(mdev, h->payload, h->length) != h->length)
-                return FALSE;
-
         /* Here the _drbd_uuid_ functions are right, current should
            _not_ be rotated into the history */
         if (get_ldev_if_state(mdev, D_NEGOTIATING)) {
@@ -3428,14 +3366,14 @@ static int receive_sync_uuid(struct drbd_conf *mdev, struct p_header80 *h)
 enum receive_bitmap_ret { OK, DONE, FAILED };
 
 static enum receive_bitmap_ret
-receive_bitmap_plain(struct drbd_conf *mdev, struct p_header80 *h,
-        unsigned long *buffer, struct bm_xfer_ctx *c)
+receive_bitmap_plain(struct drbd_conf *mdev, unsigned int data_size,
+                     unsigned long *buffer, struct bm_xfer_ctx *c)
 {
         unsigned num_words = min_t(size_t, BM_PACKET_WORDS, c->bm_words - c->word_offset);
         unsigned want = num_words * sizeof(long);
 
-        if (want != h->length) {
-                dev_err(DEV, "%s:want (%u) != h->length (%u)\n", __func__, want, h->length);
+        if (want != data_size) {
+                dev_err(DEV, "%s:want (%u) != data_size (%u)\n", __func__, want, data_size);
                 return FAILED;
         }
         if (want == 0)
@@ -3571,12 +3509,13 @@ void INFO_bm_xfer_stats(struct drbd_conf *mdev,
    in order to be agnostic to the 32 vs 64 bits issue.
 
    returns 0 on failure, 1 if we successfully received it. */
-static int receive_bitmap(struct drbd_conf *mdev, struct p_header80 *h)
+static int receive_bitmap(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned int data_size)
 {
         struct bm_xfer_ctx c;
         void *buffer;
         enum receive_bitmap_ret ret;
         int ok = FALSE;
+        struct p_header80 *h = &mdev->data.rbuf.header.h80;
 
         wait_event(mdev->misc_wait, !atomic_read(&mdev->ap_bio_cnt));
 
@@ -3596,21 +3535,21 @@ static int receive_bitmap(struct drbd_conf *mdev, struct p_header80 *h)
         };
 
         do {
-                if (h->command == P_BITMAP) {
-                        ret = receive_bitmap_plain(mdev, h, buffer, &c);
-                } else if (h->command == P_COMPRESSED_BITMAP) {
+                if (cmd == P_BITMAP) {
+                        ret = receive_bitmap_plain(mdev, data_size, buffer, &c);
+                } else if (cmd == P_COMPRESSED_BITMAP) {
                         /* MAYBE: sanity check that we speak proto >= 90,
                          * and the feature is enabled! */
                         struct p_compressed_bm *p;
 
-                        if (h->length > BM_PACKET_PAYLOAD_BYTES) {
+                        if (data_size > BM_PACKET_PAYLOAD_BYTES) {
                                 dev_err(DEV, "ReportCBitmap packet too large\n");
                                 goto out;
                         }
                         /* use the page buff */
                         p = buffer;
                         memcpy(p, h, sizeof(*h));
-                        if (drbd_recv(mdev, p->head.payload, h->length) != h->length)
+                        if (drbd_recv(mdev, p->head.payload, data_size) != data_size)
                                 goto out;
                         if (p->head.length <= (sizeof(*p) - sizeof(p->head))) {
                                 dev_err(DEV, "ReportCBitmap packet too small (l:%u)\n", p->head.length);
@@ -3618,17 +3557,17 @@ static int receive_bitmap(struct drbd_conf *mdev, struct p_header80 *h)
                         }
                         ret = decode_bitmap_c(mdev, p, &c);
                 } else {
-                        dev_warn(DEV, "receive_bitmap: h->command neither ReportBitMap nor ReportCBitMap (is 0x%x)", h->command);
+                        dev_warn(DEV, "receive_bitmap: cmd neither ReportBitMap nor ReportCBitMap (is 0x%x)", cmd);
                         goto out;
                 }
 
-                c.packets[h->command == P_BITMAP]++;
-                c.bytes[h->command == P_BITMAP] += sizeof(struct p_header80) + h->length;
+                c.packets[cmd == P_BITMAP]++;
+                c.bytes[cmd == P_BITMAP] += sizeof(struct p_header80) + data_size;
 
                 if (ret != OK)
                         break;
 
-                if (!drbd_recv_header(mdev, h))
+                if (!drbd_recv_header(mdev, &cmd, &data_size))
                         goto out;
         } while (ret == OK);
         if (ret == FAILED)
@@ -3659,17 +3598,16 @@ static int receive_bitmap(struct drbd_conf *mdev, struct p_header80 *h)
         return ok;
 }
 
-static int receive_skip_(struct drbd_conf *mdev, struct p_header80 *h, int silent)
+static int receive_skip(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned int data_size)
 {
         /* TODO zero copy sink :) */
         static char sink[128];
         int size, want, r;
 
-        if (!silent)
-                dev_warn(DEV, "skipping unknown optional packet type %d, l: %d!\n",
-                     h->command, h->length);
+        dev_warn(DEV, "skipping unknown optional packet type %d, l: %d!\n",
+                 cmd, data_size);
 
-        size = h->length;
+        size = data_size;
         while (size > 0) {
                 want = min_t(int, size, sizeof(sink));
                 r = drbd_recv(mdev, sink, want);
@@ -3679,17 +3617,7 @@ static int receive_skip_(struct drbd_conf *mdev, struct p_header80 *h, int silen
         return size == 0;
 }
 
-static int receive_skip(struct drbd_conf *mdev, struct p_header80 *h)
-{
-        return receive_skip_(mdev, h, 0);
-}
-
-static int receive_skip_silent(struct drbd_conf *mdev, struct p_header80 *h)
-{
-        return receive_skip_(mdev, h, 1);
-}
-
-static int receive_UnplugRemote(struct drbd_conf *mdev, struct p_header80 *h)
+static int receive_UnplugRemote(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned int data_size)
 {
         if (mdev->state.disk >= D_INCONSISTENT)
                 drbd_kick_lo(mdev);
@@ -3701,73 +3629,91 @@ static int receive_UnplugRemote(struct drbd_conf *mdev, struct p_header80 *h)
         return TRUE;
 }
 
-typedef int (*drbd_cmd_handler_f)(struct drbd_conf *, struct p_header80 *);
-
-static drbd_cmd_handler_f drbd_default_handler[] = {
-        [P_DATA]            = receive_Data,
-        [P_DATA_REPLY]      = receive_DataReply,
-        [P_RS_DATA_REPLY]   = receive_RSDataReply,
-        [P_BARRIER]         = receive_Barrier,
-        [P_BITMAP]          = receive_bitmap,
-        [P_COMPRESSED_BITMAP]    = receive_bitmap,
-        [P_UNPLUG_REMOTE]   = receive_UnplugRemote,
-        [P_DATA_REQUEST]    = receive_DataRequest,
-        [P_RS_DATA_REQUEST] = receive_DataRequest,
-        [P_SYNC_PARAM]      = receive_SyncParam,
-        [P_SYNC_PARAM89]           = receive_SyncParam,
-        [P_PROTOCOL]        = receive_protocol,
-        [P_UUIDS]           = receive_uuids,
-        [P_SIZES]           = receive_sizes,
-        [P_STATE]           = receive_state,
-        [P_STATE_CHG_REQ]   = receive_req_state,
-        [P_SYNC_UUID]       = receive_sync_uuid,
-        [P_OV_REQUEST]      = receive_DataRequest,
-        [P_OV_REPLY]        = receive_DataRequest,
-        [P_CSUM_RS_REQUEST]    = receive_DataRequest,
-        [P_DELAY_PROBE]     = receive_skip_silent,
+typedef int (*drbd_cmd_handler_f)(struct drbd_conf *, enum drbd_packets cmd, unsigned int to_receive);
+
+struct data_cmd {
+        int expect_payload;
+        size_t pkt_size;
+        drbd_cmd_handler_f function;
+};
+
+static struct data_cmd drbd_cmd_handler[] = {
+        [P_DATA]            = { 1, sizeof(struct p_data), receive_Data },
+        [P_DATA_REPLY]      = { 1, sizeof(struct p_data), receive_DataReply },
+        [P_RS_DATA_REPLY]   = { 1, sizeof(struct p_data), receive_RSDataReply } ,
+        [P_BARRIER]         = { 0, sizeof(struct p_barrier), receive_Barrier } ,
+        [P_BITMAP]          = { 1, sizeof(struct p_header80), receive_bitmap } ,
+        [P_COMPRESSED_BITMAP] = { 1, sizeof(struct p_header80), receive_bitmap } ,
+        [P_UNPLUG_REMOTE]   = { 0, sizeof(struct p_header80), receive_UnplugRemote },
+        [P_DATA_REQUEST]    = { 0, sizeof(struct p_block_req), receive_DataRequest },
+        [P_RS_DATA_REQUEST] = { 0, sizeof(struct p_block_req), receive_DataRequest },
+        [P_SYNC_PARAM]      = { 1, sizeof(struct p_header80), receive_SyncParam },
+        [P_SYNC_PARAM89]    = { 1, sizeof(struct p_header80), receive_SyncParam },
+        [P_PROTOCOL]        = { 1, sizeof(struct p_protocol), receive_protocol },
+        [P_UUIDS]           = { 0, sizeof(struct p_uuids), receive_uuids },
+        [P_SIZES]           = { 0, sizeof(struct p_sizes), receive_sizes },
+        [P_STATE]           = { 0, sizeof(struct p_state), receive_state },
+        [P_STATE_CHG_REQ]   = { 0, sizeof(struct p_req_state), receive_req_state },
+        [P_SYNC_UUID]       = { 0, sizeof(struct p_rs_uuid), receive_sync_uuid },
+        [P_OV_REQUEST]      = { 0, sizeof(struct p_block_req), receive_DataRequest },
+        [P_OV_REPLY]        = { 1, sizeof(struct p_block_req), receive_DataRequest },
+        [P_CSUM_RS_REQUEST] = { 1, sizeof(struct p_block_req), receive_DataRequest },
+        [P_DELAY_PROBE]     = { 0, sizeof(struct p_delay_probe93), receive_skip },
         /* anything missing from this table is in
          * the asender_tbl, see get_asender_cmd */
-        [P_MAX_CMD]         = NULL,
+        [P_MAX_CMD]         = { 0, 0, NULL },
 };
 
-static drbd_cmd_handler_f *drbd_cmd_handler = drbd_default_handler;
-static drbd_cmd_handler_f *drbd_opt_cmd_handler;
+/* All handler functions that expect a sub-header get that sub-heder in
+   mdev->data.rbuf.header.head.payload.
+
+   Usually in mdev->data.rbuf.header.head the callback can find the usual
+   p_header, but they may not rely on that. Since there is also p_header95 !
+ */
 
 static void drbdd(struct drbd_conf *mdev)
 {
-        drbd_cmd_handler_f handler;
-        struct p_header80 *header = &mdev->data.rbuf.header;
+        union p_header *header = &mdev->data.rbuf.header;
+        unsigned int packet_size;
+        enum drbd_packets cmd;
+        size_t shs; /* sub header size */
+        int rv;
 
         while (get_t_state(&mdev->receiver) == Running) {
                 drbd_thread_current_set_cpu(mdev);
-                if (!drbd_recv_header(mdev, header)) {
-                        drbd_force_state(mdev, NS(conn, C_PROTOCOL_ERROR));
-                        break;
+                if (!drbd_recv_header(mdev, &cmd, &packet_size))
+                        goto err_out;
+
+                if (unlikely(cmd >= P_MAX_CMD || !drbd_cmd_handler[cmd].function)) {
+                        dev_err(DEV, "unknown packet type %d, l: %d!\n", cmd, packet_size);
+                        goto err_out;
                 }
 
-                if (header->command < P_MAX_CMD)
-                        handler = drbd_cmd_handler[header->command];
-                else if (P_MAY_IGNORE < header->command
-                     && header->command < P_MAX_OPT_CMD)
-                        handler = drbd_opt_cmd_handler[header->command-P_MAY_IGNORE];
-                else if (header->command > P_MAX_OPT_CMD)
-                        handler = receive_skip;
-                else
-                        handler = NULL;
+                shs = drbd_cmd_handler[cmd].pkt_size - sizeof(union p_header);
+                rv = drbd_recv(mdev, &header->h80.payload, shs);
+                if (unlikely(rv != shs)) {
+                        dev_err(DEV, "short read while reading sub header: rv=%d\n", rv);
+                        goto err_out;
+                }
 
-                if (unlikely(!handler)) {
-                        dev_err(DEV, "unknown packet type %d, l: %d!\n",
-                            header->command, header->length);
-                        drbd_force_state(mdev, NS(conn, C_PROTOCOL_ERROR));
-                        break;
+                if (packet_size - shs > 0 && !drbd_cmd_handler[cmd].expect_payload) {
+                        dev_err(DEV, "No payload expected %s l:%d\n", cmdname(cmd), packet_size);
+                        goto err_out;
                 }
-                if (unlikely(!handler(mdev, header))) {
+
+                rv = drbd_cmd_handler[cmd].function(mdev, cmd, packet_size - shs);
+
+                if (unlikely(!rv)) {
                         dev_err(DEV, "error receiving %s, l: %d!\n",
-                            cmdname(header->command), header->length);
-                        drbd_force_state(mdev, NS(conn, C_PROTOCOL_ERROR));
-                        break;
+                            cmdname(cmd), packet_size);
+                        goto err_out;
                 }
         }
+
+        if (0) {
+        err_out:
+                drbd_force_state(mdev, NS(conn, C_PROTOCOL_ERROR));
+        }
 }
 
 void drbd_flush_workqueue(struct drbd_conf *mdev)
@@ -3980,27 +3926,28 @@ static int drbd_do_handshake(struct drbd_conf *mdev)
 {
         /* ASSERT current == mdev->receiver ... */
         struct p_handshake *p = &mdev->data.rbuf.handshake;
-        const int expect = sizeof(struct p_handshake)
-                          -sizeof(struct p_header80);
+        const int expect = sizeof(struct p_handshake) - sizeof(struct p_header80);
+        unsigned int length;
+        enum drbd_packets cmd;
         int rv;
 
         rv = drbd_send_handshake(mdev);
         if (!rv)
                 return 0;
 
-        rv = drbd_recv_header(mdev, &p->head);
+        rv = drbd_recv_header(mdev, &cmd, &length);
         if (!rv)
                 return 0;
 
-        if (p->head.command != P_HAND_SHAKE) {
+        if (cmd != P_HAND_SHAKE) {
                 dev_err(DEV, "expected HandShake packet, received: %s (0x%04x)\n",
-                     cmdname(p->head.command), p->head.command);
+                     cmdname(cmd), cmd);
                 return -1;
         }
 
-        if (p->head.length != expect) {
+        if (length != expect) {
                 dev_err(DEV, "expected HandShake length: %u, received: %u\n",
-                     expect, p->head.length);
+                     expect, length);
                 return -1;
         }
 
@@ -4058,10 +4005,11 @@ static int drbd_do_auth(struct drbd_conf *mdev)
         char *response = NULL;
         char *right_response = NULL;
         char *peers_ch = NULL;
-        struct p_header80 p;
         unsigned int key_len = strlen(mdev->net_conf->shared_secret);
         unsigned int resp_size;
         struct hash_desc desc;
+        enum drbd_packets cmd;
+        unsigned int length;
         int rv;
 
         desc.tfm = mdev->cram_hmac_tfm;
@@ -4081,33 +4029,33 @@ static int drbd_do_auth(struct drbd_conf *mdev)
         if (!rv)
                 goto fail;
 
-        rv = drbd_recv_header(mdev, &p);
+        rv = drbd_recv_header(mdev, &cmd, &length);
         if (!rv)
                 goto fail;
 
-        if (p.command != P_AUTH_CHALLENGE) {
+        if (cmd != P_AUTH_CHALLENGE) {
                 dev_err(DEV, "expected AuthChallenge packet, received: %s (0x%04x)\n",
-                    cmdname(p.command), p.command);
+                    cmdname(cmd), cmd);
                 rv = 0;
                 goto fail;
         }
 
-        if (p.length > CHALLENGE_LEN*2) {
+        if (length > CHALLENGE_LEN * 2) {
                 dev_err(DEV, "expected AuthChallenge payload too big.\n");
                 rv = -1;
                 goto fail;
         }
 
-        peers_ch = kmalloc(p.length, GFP_NOIO);
+        peers_ch = kmalloc(length, GFP_NOIO);
         if (peers_ch == NULL) {
                 dev_err(DEV, "kmalloc of peers_ch failed\n");
                 rv = -1;
                 goto fail;
         }
 
-        rv = drbd_recv(mdev, peers_ch, p.length);
+        rv = drbd_recv(mdev, peers_ch, length);
 
-        if (rv != p.length) {
+        if (rv != length) {
                 dev_err(DEV, "short read AuthChallenge: l=%u\n", rv);
                 rv = 0;
                 goto fail;
@@ -4122,7 +4070,7 @@ static int drbd_do_auth(struct drbd_conf *mdev)
         }
 
         sg_init_table(&sg, 1);
-        sg_set_buf(&sg, peers_ch, p.length);
+        sg_set_buf(&sg, peers_ch, length);
 
         rv = crypto_hash_digest(&desc, &sg, sg.length, response);
         if (rv) {
@@ -4135,18 +4083,18 @@ static int drbd_do_auth(struct drbd_conf *mdev)
         if (!rv)
                 goto fail;
 
-        rv = drbd_recv_header(mdev, &p);
+        rv = drbd_recv_header(mdev, &cmd, &length);
         if (!rv)
                 goto fail;
 
-        if (p.command != P_AUTH_RESPONSE) {
+        if (cmd != P_AUTH_RESPONSE) {
                 dev_err(DEV, "expected AuthResponse packet, received: %s (0x%04x)\n",
-                    cmdname(p.command), p.command);
+                        cmdname(cmd), cmd);
                 rv = 0;
                 goto fail;
         }
 
-        if (p.length != resp_size) {
+        if (length != resp_size) {
                 dev_err(DEV, "expected AuthResponse payload of wrong size\n");
                 rv = 0;
                 goto fail;
@@ -4474,9 +4422,8 @@ static int got_OVResult(struct drbd_conf *mdev, struct p_header80 *h)
         return TRUE;
 }
 
-static int got_something_to_ignore_m(struct drbd_conf *mdev, struct p_header80 *h)
+static int got_skip(struct drbd_conf *mdev, struct p_header80 *h)
 {
-        /* IGNORE */
         return TRUE;
 }
 
@@ -4504,7 +4451,7 @@ static struct asender_cmd *get_asender_cmd(int cmd)
         [P_BARRIER_ACK]     = { sizeof(struct p_barrier_ack), got_BarrierAck },
         [P_STATE_CHG_REPLY] = { sizeof(struct p_req_state_reply), got_RqSReply },
         [P_RS_IS_IN_SYNC]   = { sizeof(struct p_block_ack), got_IsInSync },
-        [P_DELAY_PROBE]     = { sizeof(struct p_delay_probe93), got_something_to_ignore_m },
+        [P_DELAY_PROBE]     = { sizeof(struct p_delay_probe93), got_skip },
         [P_MAX_CMD]         = { 0, NULL },
         };
         if (cmd > P_MAX_CMD || asender_tbl[cmd].process == NULL)
@@ -4515,7 +4462,7 @@ static struct asender_cmd *get_asender_cmd(int cmd)
 int drbd_asender(struct drbd_thread *thi)
 {
         struct drbd_conf *mdev = thi->mdev;
-        struct p_header80 *h = &mdev->meta.rbuf.header;
+        struct p_header80 *h = &mdev->meta.rbuf.header.h80;
         struct asender_cmd *cmd = NULL;
 
         int rv, len;